The weathering of igneous rock has resulted in the formation of various deposits of iron oxides and carbonates; and these comprise the principal mineral sources of the metal. In addition, the iron oxides and carbonates commonly occur in natural association with such other minerals as sulfides, silicates and phosphates. Moreover, certain steel-making processes require that the iron ore being charged be low in phosphorus because that element is not readily oxidized to an acceptable slag by oxygen-containing gases; and as a consequence, there is reduced marketability for iron ore pellets, for example those based on magnetite ore, which posses a phosphorus content above 0.05% by weight.
Accordingly, in the past, efforts have been made to remove the principal phosphorus-bearing contaminant mineral, apatite, from magnetite ore by using beneficiation procedures. However, the fatty acid-based flotation reagents generally employed heretofore have exhibited poor selectivity, allowing appreciable amounts of iron ore to be floated off with the apatite, thus reducing yields uneconomically.
An important object of the present invention is therefore to provide an improved method of beneficiating magnetite ore concentrate to remove apatite in a highly economical and selective manner.
A more general object of the invention is to provide new and improved methods and reagents for beneficiating iron ore.
Another object of the invention is to provide a self-frothing beneficiation reagent for separating apatite from an iron ore slurry.